But one of his most unsettling beliefs is still his acceptance of the value of torture. “In my opinion, it works,” he told Sean Hannity of Fox News early last year.

Previously, anyone alarmed by Mr. Trump’s cavalier embrace of government-sanctioned cruelty was reassured by his vow to accept the advice of his defense secretary, Jim Mattis, who opposes torture and promised at his Senate confirmation hearing that he would uphold American and international laws against it.

Now we have reason to be uneasy yet again.

When it comes to torture, no American officials have been more practiced in those heinous dark arts than the officers and employees of the Central Intelligence Agency who applied it to terrorism suspects after 9/11. Few American officials were so directly involved in that frenzy of abuse, which began under President George W. Bush and was ended by President Barack Obama, as Gina Haspel.

On Tuesday, in announcing that he had dismissed Rex Tillerson as secretary of state and was replacing him with Mike Pompeo, the C.I.A. director, Mr. Trump said that Mr. Pompeo’s successor would be his deputy, Ms. Haspel.

Ms. Haspel ran the first detention site in Thailand and oversaw the brutal interrogation of the Abd al-Rahim al-Nashiri, who was accused of bombing the U.S.S. Cole and was waterboarded three times.

The sessions were videotaped and the recordings stored in a safe at the C.I.A. station in Thailand until they were ordered destroyed in 2005. And who did that? By then, Ms. Haspel was at C.I.A. headquarters, and while the agency said the decision to destroy evidence was made by her boss at the time, Jose Rodriguez, Ms. Haspel’s name was on the cable with the destruction orders.

In 2013, these activities were of such concern that Senator Dianne Feinstein of California, the senior Democrat on the Senate Intelligence Committee, blocked Ms. Haspel’s promotion to be head of the agency’s clandestine service. Since then the two have spent time together, leading Ms. Feinstein on Tuesday to describe Ms. Haspel as a “good deputy” and to say she would wait until the confirmation hearing to make a judgment on the appointment.

Senator John McCain, Republican of Arizona and a former prisoner of war, insisted that during the confirmation process, Ms. Haspel must “explain the nature and extent of her involvement” in the interrogation program. Senator Ron Wyden, Democrat of Oregon, said her roles overseeing the waterboarding of detainees and the destruction of tapes were troubling. He and the American Civil Liberties Union called for Ms. Haspel’s C.I.A. records to be declassified as part of her nomination.

The use of torture and secret foreign prisons — think of the deeply disgraceful events at Abu Ghraib prison in Iraq — was a boon to terrorist groups, helping their propaganda and recruitment efforts. Such activities were also an irritant to key allies and even put American forces and personnel at risk of legal liability and being subjected to harsh treatment when they are detained.

Ms. Haspel is reportedly respected by many C.I.A. officers. But she effectively ran an illegal program, and her promotion to such a top administration position, unless she forcefully renounces the use of torture during her confirmation hearing, would send an undeniable signal to the agency, and the country, that Mr. Trump is indifferent to this brutality, regardless of what Secretary Mattis believes. Members of Congress and public interest groups need to stand up and make clear that, otherwise, the appointment is wrong.

Correction:

An earlier version of this editorial referred incorrectly to the extent of Ms. Haspel’s involvement with torture. She oversaw the torture of the detainee Abd al-Rahim al-Nashiri at a secret site in Thailand. She did not oversee the torture of Abu Zubaydah.

A version of this article appears in print on , on Page A26 of the New York edition with the headline: Will a Torturer Be Allowed to Lead the C.I.A.?. Order Reprints | Today’s Paper | Subscribe